Most people when sleeping or resting will, periodically, switch position between lying on their back and lying on either side. Due to the shape of the human body, an ideal support for use when sleeping or resting on one's side will be at a different height to a support for use when sleeping on one's back.
More specifically, it is important to maintain the head in a neutral position (as shown in FIGS. 15 and 17) regardless of whether the subject is lying on his/her back or side. A neutral position when lying on one's back would be described as the head not being pushed too far forward or allowed to tilt too far back. A neutral position when lying on one's right hand side would be described as the head not being raised too far up, so tilted to the left, or allowed to drop down, so tilted the right. When a subject is lying on their left hand side a neutral position would be with the head not pushed too far up, so being tilted to the right, or being allowed to drop down, so being tilted to the left.
Any deviation from this neutral position can result in neck strain, particularly if the deviation is prolonged, by causing over-extension or contraction of the ligaments in the neck, and corresponding contraction or stretching of the surrounding neck muscles. Deviation may also place undue pressure on the intervertebral discs. The result of the strain can be discomfort whilst sleeping or resting, and also continuing discomfort in the neck area the following day.
Typical pillows only allow one height of support. This is the same regardless of sleeping position. If the pillow is too high (as shown in FIG. 16) then whilst a person is lying on their back, the head will be too elevated, resulting in neck strain through over stretching of the neck ligaments at the rear of the neck. Whilst lying on one's side, if the pillow is too low (as shown in FIG. 18) the head will pull the neck down resulting in neck strain through over stretching of neck ligaments on the upper side of the neck and compression of the facet joints. As such, conventional pillows offer a ‘compromise’ and often do not offer the correct height of support for either sleeping position.
Ergonomic pillows have been on the market for some years. Although these can improve the situation somewhat, they have several drawbacks, not least of which is the expense of such pillows.
CN201263564 (HEQIAN) is an example of such an ergonomic pillow. This document discloses a pillow structure having regulating pads placed under three pillows: one main pillow and two auxiliary pillows on either side. The regulating pads regulate the height of the pillows. In some embodiments shown, the main pillow is lower than the two auxiliary pillows. In this embodiment there is one regulating pad placed under each of the pillows. In another embodiment shown, the main pillow is the same height as the auxiliary pillows. In that embodiment, multiple regulating pads are placed underneath the main pillow. A pillow sleeve surrounds the pillow structure. The modular nature of this pillow structure means that it is likely to be expensive. Being a pillow in itself, the disclosed structure is an alternative to a conventional pillow. Having to replace their conventional pillow is an inconvenience to the user.
CN201743375 (YONGJIU) also discloses an ergonomic pillow. The disclosed pillow is modular, being formed of a plurality of inner pillow blocks connected together. The modularity allows the pillow to form different heights. Because each inner block is 2-4 cm in height, the height of the pillow at any one point will be a multiple of 2-4. In none embodiment shown, the pillow is shaped so that it is lower in the middle and higher at the sides. As with the pillow of CN201263564, this pillow is likely to be expensive and inconvenient for the user.
Thus, there is a need for a method of reducing the risk of neck strain and promoting comfortable sleep or rest, regardless of whether the subject is lying on their back or side, that is inexpensive and convenient for the user. The present invention, in its various embodiments, some of which are described here, aims to meet this need.